A number of catheter assemblies are known for the introduction of a polymeric cannula into a vein, artery or body cavity of a living subject for infusion or extraction of fluids.
In one apparatus, a steel needle or stylet (hereafter referred to as needle, for convenience) is sized to fit within the duct of the cannula and the piercing tip of the needle exits its distal end. The needle is inserted into the living subject after which the needle is removed from the cannula, leaving the cannula behind with at least its distal end in the subject. Additional tubing can be attached thereto or medicaments or nutrients can be caused to flow through the cannula into the subject. Also, the cannula can be relatively long and can be fed into the vein, artery or body cavity through an appropriate catheter holder which can itself be attached to the body adjacent the point of entry of the cannula through the skin. The needle is removed by having an extractor, which may be an extraction wire or a continuation of the needle, extending longitudinally from its proximal end. The extractor can pass through any additional length of the cannula and also passes through the hub which holds the cannula and out the proximal end of the hub.
A problem which exists with such a catheter assembly is that when the extractor is used to pull the needle or stylet through the cannula and then through the hub, one ends up with a sharp instrument exposed, namely the needle or stylus, which may be infected with virulent bacteria, virus and the like. In such instances hospital personnel can inadvertently stab themselves with the needle or stylet, even if the personnel are wearing rubber gloves, and thereby contact an infectious disease, such as AIDS, hepatitis, or the like.
Several needle encasing or protecting apparatus have been designed to prevent hospital personnel from being accidently stabbed by the needles of conventional barrel and plunger hypodermic syringes where such needles are not utilized to position a cannula and where such needles do not have an extraction wire attached to them and are not pulled through the cannula prior to being discarded. For example, U.S. Pat. No. 4,643,199, issued Feb. 17, 1987 to B. P. Jennings, Jr. and P. M. Kivlighan, U.S. Pat. No. 4,650,468, issued Mar. 17, 1987 to B. P. Jennings, Jr., U.S. Pat. No. 4,675,005, issued Jun. 23, 1987 to J. DeLuccia and U.S. Pat. No. 4,681,567, issued Jul. 21, 1987 to E. J. Masters and P. L. Ebaugh each show a the needle being withdrawn into the barrel of a conventional hypodermic syringe.
U.S. Pat. No. 4,676,783, issued Jun. 30, 1987 to J. C. Jagger, R. D. Pearson and P. C. Guyenet relates to a needle assembly wherein a needle is withdrawable into a cylinder to which wings are attached for gripping. The proximal end of the needle is wedged in place thus holding the needle within the cylinder.
One apparatus, sold under the trademark "SafeSide" by LUMED, removes a needle from the inside of a cannula after the needle and cannula have been inserted in the blood vessel. The apparatus is in the nature of two relatively slidable tubes, one within the other. A hub is attached to the distal end of the inner tube, the hub carrying a plastic cannula extending longitudinally therefrom. The needle extends concentrically within the cannula and extends beyond the distal end of the cannula for piercing the skin and the blood vessel. Once the needle and cannula have been inserted in a blood vessel the outer tube is moved proximally relative to the inner tube whereby the needle is withdrawn from the cannula and ends up being positioned within the inner tube. Once the tubes have been pulled apart as far as is possible they lock into place so that the needle is kept covered.
None of the above described apparatus is, however, adaptable to receiving and protecting a needle or stylet which is withdrawn through a hub, for example, utilizing an extraction wire. Also, such an assembly is limited in that one cannot feed a desired length of catheter into the blood vessel but, instead, can only insert the length of catheter which originally covered the needle (from the skin line inwardly into the blood vessel).
The present invention is directed to overcoming one or more of the problems as set forth above.